JPS6130687B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the shape of a rolled material in a tandem rolling mill.

Generally, rolled materials, particularly thin plates, are manufactured by rolling using rolling rolls, but in this case, each time they are rolled, elongation occurs in the rolling direction, resulting in a thin plate. When a rolled material is rolled, there is always a deflection between the work roll and the backing roll. Also, during rolling, heat of deformation is generated in the rolled material, and frictional heat is generated between the rolled material and the work roll, and between the work roll and the backing roll. is accumulated, resulting in a difference in the amount of crown between the work roll and the backing roll.

Therefore, the thickness of the exit side of the last stand is almost never distributed uniformly in the width direction. When the rolled material is wound on a tension reel in this state, the coil diameter of the tension reel differs from the center of the width of the sheet to the ends. Due to this difference in coil diameter, the distance between the tension reel and the final stand will be different between the center and edge of the board width. For this reason, the tension applied to the rolled material is smaller at the edge of the plate width,
The center is larger. On the other hand, as the rolling time becomes longer, the thermal crowns of the work roll and backing roll become larger, and the shape of the rolled material becomes intermediately elongated. Therefore, the tension fluctuations due to the plate crown and the tension fluctuations due to the thermal crowns of the work roll and backing roll cancel each other out, making it impossible to detect defects in the shape of the rolled material.

Conventionally, a shape detector is installed between the tension reel and the final stand in order to detect shape defects in rolled material as described above, but shape detectors are installed between the tension reel and the final stand. Since the tension fluctuations canceled each other out, the tension distribution of the rolled material hardly changed, and it was not possible to detect shape defects, especially mid-elongation, in the rolled material.

The present invention aims to eliminate the above-mentioned drawbacks and provide a method for detecting the shape of a rolled material that can realize a highly refined shape detection of the rolled material.

FIG. 1 is a block diagram embodying an embodiment of the present invention, in which 1 is a rolled material, 10 is a work roll of the final stand, 20 is a deflector roll, 30 is a tension reel, 100 is a coil diameter detection device, 1
10 a plate crown detection device for rolled material, 120 a shape detector, 130 a calculation device, 140 a comparator, 1
50 is a shape defect calculation device.

Next, a method for detecting shape defects in a rolled material will be explained in detail with reference to the block diagram of FIG. 200 according to the coil diameter of the tension reel detected at 100 and the plate crown of the rolled material detected at 110.
Calculate the distribution of the tension reel coil diameter with
In 210, the distribution of the distance between the final stand and the tension reel is calculated based on the distribution of the coil diameter calculated in 200, and in 220, the amount of tension variation caused by the distance distribution is calculated, and the standard pattern is calculated. Repair the tension distribution. At 140, the tension distribution detected at 120 is compared with the tension distribution of the standard pattern corrected at 220. 150 is 140
Defects in the shape of the rolled material are detected based on the tension distributions compared.

Next, the plate crown, the coil diameter, and the amount of variation in tension, which are the basis of this invention, will be described. In FIG. 3, the coil diameter at the center of the plate width is Rc, and the coil diameter at the ends is Re. Also, let Hc be the thickness of the center of the width of the plate crown, and He be the thickness of the edge. At this time, the difference in distance between the center and edge of the plate between the final stand and the tension reel, △Lce, is △Lce=Rc-Re=Rc-{Rc-Ro/hc・he +Ro}...(1) However, Ro is It is the spool diameter.

becomes. This distance difference affects the tension distribution between the final stand and the tension reel.
The tension difference △σec between the center and edge of the plate is △σec = E・△Lce/L=E/L・hc−he/hc
・(Rc −Re) ...(2) becomes.

The tension distribution between the final stand and the tension reel varies by the amount expressed by equation (2).

Now, the work roll and the backing roll thermally expand as the rolling time elapses. In particular, the temperature difference between the center and edge of the plate increases. for example,
Consider a case where the temperature at the center of the plate rises by 1°C. If the radius of the work roll is 250mm, the radius of the work roll will expand by 2.5μ. In other words, judging from the shape of the rolled material, this means that the center plate of the 2.5μ plate is elongated.

In this manner, the tension distribution between the final stand and the tension reel decreases near the center due to the thermal expansion of the work roll and backing roll.

As described above, as the rolling time elapses, the coil diameter of the tension reel has a large distribution in the width direction of the plate due to the plate crown, and therefore the tension at the plate end decreases. In addition, the tension in the center of the plate decreases due to thermal expansion of the work rolls and the like. Therefore, it appears that there is no tension variation across the entire width of the plate, and even if the shape detector detects the tension distribution in the width direction of the rolled material, it is likely that the rolled material is defective in shape, i.e. Unable to detect elongation. Therefore, by calculating the tension fluctuation due to the distribution of the coil diameter of the tension reel due to the plate crown and correcting the tension distribution detected by the shape detector, it is possible to detect a shape defect in the rolled material.

This invention has been made in view of the above points, and has an object of detecting the crown of a plate wound on a tension reel and detecting the coil diameter of the rolled material at the center of the plate wound on the tension reel. The method detects the coil diameter distribution, calculates the tension variation due to the plate crown in the tension distribution, and compares the calculated result with the tension distribution detected by the shape detector to detect shape defects in the rolled material. In particular, it detects middle elongation. In this way, the present invention attempts to provide a method for detecting defects in the shape of a rolled material by detecting the plate crown and the coil diameter of the tension reel on the outlet side of the rolled material of the final stand.

FIGS. 4 and 5 are block diagrams embodying other embodiments of the invention. In Figure 4, 11
Reference numeral 5 denotes an X-ray thickness meter, which can scan in the width direction of the sheet in order to detect the distribution of sheet thickness in the width direction of the sheet.

In FIG. 5, 131 is a detection device that detects the rotation speed of the work roll of the final stand, 132 is a detection device that detects the rotation speed of the deflector roll,
133 is a detection device that detects the rotation speed of the tension reel, and 141 is an arithmetic device that uses 131, 132, and 133 to calculate the coil diameter of the tension reel.

As described above, the present invention detects the distribution of the coil diameter of the tension reel of rolled material in the plate width direction by detecting the coil diameter of the tension reel and also detecting the plate thickness distribution on the exit side of the final stand. The shape of the rolled material is detected using the result of calculating the tension fluctuation between the final stand and the tension reel and the tension distribution detected by the shape detector. Defects can be detected more accurately.

[Brief explanation of the drawing]

Fig. 1 is a block diagram embodying an embodiment of the method for detecting the shape of rolled material according to the present invention, Fig. 2 is a detailed flowchart of the main parts of Fig. 1, and Fig. 3 is a tension reel coil diameter and tension fluctuation. 4 and 5 are block diagrams embodying other embodiments of the present invention. In the figure, 1 is a rolled material, 10 is a rolling roll, 20 is a deflector roll, 30 is a tension reel,
100 is a detector, 110 is a plate crown detector, 1
20 is a shape detector, 130, 140, 150 are computing units, 115 is an X-ray thickness meter, 131, 132, 1
33 is a rotation speed detector. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 In a tandem rolling mill, a shape detector installed between the final stand and the tension reel detects the shape of the exit side of the final stand and detects the coil diameter when the rolled material is wound around the tension reel. , further detects the plate crown of the exit side plate thickness of the final stand, and calculates the amount of tension variation due to the plate crown based on the plate crown of the exit side plate thickness of the final stand detected above and the coil diameter of the tension reel. The method is characterized in that a deviation in the tension distribution of the rolled material detected by the above-mentioned shape detector is calculated, and based on this result, a shape defect in the rolled material is detected. A method for detecting the shape of rolled material.